Recently, increased efforts have been devoted to improving the efficiency of reading written or printed information from the face of paper documents. For example, in the area of processing of financial documents such as checks, deposit slips, remittance advice stubs, and the like, the use of image processing technology has been receiving increased application. In accordance with typical image processing techniques, documents are transported to a scanning station at which a camera and associated electronics are used to capture and digitize all or a portion of the image of a face of each of the documents. The digitized image is stored and subsequently processed, for example, to display the image (by way of a CRT, for instance) to an operator for keying specific information into the system processor; the document images also being used, for example, for bank statement preparation and/or reproduced for archival storage on microfilm, magnetic tape, optical discs, etc.
A chief advantage of this technology is that the document images, rather than the documents, are used for viewing and processing, thus increasing the speed and overall flexibility of the document processing operation, as well as reducing or eliminating the need for retaining the documents themselves. The archiving, cataloging, and other processes which are required for record-keeping purposes can be more efficiently carried out, and additionally, the space required for such electronically-reproduced forms can be much reduced from that heretofore required.
The increasing use of background illustrations and safety patterns on checks and other items, however, poses special problems for the image processing of these finanical documents. First, these patterns and illustrations increase the amount of data bit storage required in the system processor. Secondly, the various scenes of mountains, seashores, animals, and the like which are imprinted on the checks oftentimes obscure and interfere with pertinent data from being image captured from the face of the document, especially the signatures and dollar amounts written thereon. In particular, these patterns make it difficult, if not impossible, for the camera to discriminate between the important information which is to be captured from the face of the check and the background illustrations. Amplifying this problem is that conventional image processing normally relies upon front lighting of the document and such front lighting actually enhances the background patterns, which in turn further obscures the information or data which is to be detected or captured from the face of the document.